Contribution of the nonresonant mechanism to the double and single differential distributions over the invariant variables in the reaction e++e−→N+N¯+π0

Abstract

The general analysis of the differential cross section and various polarization observables is performed for the process ${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}N+\overline{N}+{\ensuremath{\pi}}^{0}$ assuming that the annihilation occurs through the exchange of one virtual photon. The dependence of the differential distributions over invariant variables is derived for the reaction ${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}N+\overline{N}+{\ensuremath{\pi}}^{0}$ in the so-called nonresonant mechanism, applying the conservation of the hadron electromagnetic currents and the P-invariance of the hadron electromagnetic interaction. The detection in an exclusive experimental setup where the nucleon (or antinucleon) and pion are detected in coincidence is considered. A number of single and double differential distributions have been calculated analytically and numerical estimates are given for the $p\overline{p}{\ensuremath{\pi}}^{0}$ and $n\overline{n}{\ensuremath{\pi}}^{0}$ channels, in the Born (nonresonant) approximation, in the energy range from threshold up to $s=16\text{ }\text{ }{\mathrm{GeV}}^{2}$.